1. Field of the Invention
The present invention concerns a method of manufacturing supports for electrical circuits.
2. Description of the Prior Art
It is known that to manufacture supports for electrical circuits, in particular so-called "printed" circuits, it is necessary to carry out a certain number of processing phases on a board so that this is finally provided with the necessary conductive circuits whereas it is itself made from an insulative material.
The board must also have numerous holes through it into which may be inserted the connecting leads of electrical and electronic components, with the result that the walls of these holes must also be covered by a conductive deposit providing an electrical connection between the two sides of the board.
Unfortunately, the boards must also have in them holes used to position them during automatic insertion of electronic components, usually referred to as "locating" holes.
Automatic component insertion is a high-precision operation and because of this the locating holes must be very accurately placed and their diameter is subject to extremely severe tolerance limits, in the order of 4/100 millimeter at most.
Conductive coatings obtained by electrolytic means cannot guarantee such accuracy, however.
There are also cases where it is necessary to ensure that holes other than the locating holes retain the same diameter and surface state as they had before electrolytic deposition of the conductive material.
The present invention offers a solution to these problems and makes it possible to obtain supports for electrical circuits with holes, especially locating holes, retaining the precise diameter determined by the machine which formed the holes.